Epstein-Barr virus associated smooth muscle tumors in solid organ transplant recipients: Incidence over 31 years at a single institution and review of the literature

Abstract

Introduction: Epstein-Barr virus (EBV) associated smooth muscle tumors (EBV-SMT) are a rare complication of solid organ transplantation (SOT). Incidence data related to this EBV-SMT are limited. EBV DNA is universally present in these tumors. How these cells get infected with EBV, whether this is a result of primary EBV infection vs reactivation, and how persistent active EBV infection post-transplant influences EBV-SMT pathogenesis remains unknown. Methods: Among 5006 SOT recipients (474 pediatric, 4532 adult) receiving SOT at our center between Jan 1984 and Dec 2015, three cases of post-transplant EBV-SMT were identified. Results: All cases were pediatric heart transplants who were EBV seronegative prior to transplant, and experienced primary EBV infection with persistently elevated EBV viral loads, despite antiviral therapy. Two are deceased at 3.2 and 0.9 years post-diagnosis, while one remains alive 6.2 years post diagnosis. The overall local incidence of post-transplant EBV-SMT at our institution was 0.7 (95% CI, 0.2-1.7) per 1000 patient years, and 2.6 (95% CI, 0.6-6.7) per 1000 patient years in pediatric heart transplants. A literature review identified 36 pediatric and 51 adult cases of post-transplant EBV-SMT. Conclusions: We hypothesize that pre-transplant EBV seronegativity, followed by primary EBV infection and persistently high EBV viral loads, represents a unique risk factor for post-transplant EBV-SMT. Pediatric heart transplant recipients were found to be disproportionately affected by post-transplant EBV-SMT at our institution.